Fluid-pressure brake



April 2, 1929. T. H. THOMAS 1,707,288

FLUID PRESSURE 13mm:y l

Filed Jan. 28, 1927' 6 I .u' .Il i HUI" III 4 62 sa 62 I9 /6/4/3 6, 2124- /s /l- 5,513 5e -yf /l/ INVENTOR u THoMAs HrrHoMAs ATTQRNY lli Patented Apr. 2, 1929.

THOMAS H. mnoivrae, onnnenuroon, nnn'uovnvai neuen Ain-,nanna contraria', on wim/Ianni OF PENNSYLVANIA.

Parear OFFICE,

feierten ro THE Waerme- :a'evtvania a conPoRA'rIoN Application tiled January 28, 193'. Serial No. 164,212.

lhie invention relates to fluid preaeure brakes, and more particularly to the `lnralie control equipment on the locomotive.

ln the usual locomotive lluid pressure bralre equipment the :uiten` lc brake valve device is normally carried lin running' peeition, while the brakes are held released, and in :said position illuid under pressure supplied to the `bi'alre pipe through il'eed valve device, to maintain the pressure in the brake pipeat a predetermined degree.

llihen the brakes are in release poeition, if a sudden `reducticm in brake pipe preeeure ie iiiitiated ata point in the train, other than by `operation ol' the automatic brake valve device, lsaid reduction will be propagated serially throughout the train bv the Well known quick Serial action, and the brakes will be applied. It, under euch a condition, the brake valve device ie not moved from the running; position to the lap pi'isliition, eo ae to cut oll the flow of 'fluid to the brake pipe, `the brakes on the locomotive and on the care at the head ot the train are liable to be released, by the continued flow of 'duid to the brake pipe. i

Sonie types of brake equipment are not adapted to propagate quick serial action in emergenc't7 after a light service reduction in brake pipe preeeure has been made, and if a sufficient number4 ot care equipped with auch types of brakev apparatus happen to be together, itmay result inthe failure to propagate quick serial action to the locomotive, even though other care in the train mat7 be provided With brakepipe vent valve devices, adapted to cause quick serial action after a service reduction in brake pipe pressure. Y t

Under the above conditions, however, the operation of the vent valve devices; in the train causes a brake pipereduction in excess of a full service reduction before Said de vices cloee and cut olf communication betvveen the brake pipe and the atmosphere. The over reduction` in brake pipe preeeure causedby operation ot the vent valve de vices ellects an application of the brakes, but the fluid under preesure supplied bv the feed valve device, With the brake valve` de vice in running,V position, `tende to cause a release of the bra-kes on the head end of the train, the same as after an emergency application.

The principal "object of my invention is to` provide means; for automatically cutting olf the flow oli third` lo the brake pipe at the bi'altcvalve device to euenrc retaining; an`

application of thebrakce on ,a train, either alter the occurrence ofan undeeired emergency application ol an undaaired over service reduction iu brake pipe preneur-e, with the ln'ake valve device in running;position.

Aln the accompanying' drawingpthe single ligureie asectional view of a brake control equipn'ient, embodying; my invention.

The apparatue ahoivn in the drawing includes a `brake valve device l, a distributing valve device 2, and the usual 'l'ec'dvalve device 3. .i

ilhe brake valve device l comprises a casingV having a valve chamber 4c, containing` the ueual rotary valve 5 adapted to be operated by a handle G. `lnchidcd in the casing is the uaual equalizinp; dischargevalve mechanism coinprieinga pieton 7, having the chamber El at one Side connected to the cqualiaing rerficrvoir 9 and the chzunberflll at the oppoeitc side connected to the brake pipe ll.. Pieton Titi adapted to operate a discharge valve l2 for venting;` iuid 'lromythe brake pipe 1l. E

Also included in the brake valve casing ie a cut olif valve mechanism comprising a valve 13 contained in a chamber 1ct and adapted, in one punit-ion, to Seal against a Seat ring1 15. A pieton 16 connected to the valve 13 by a stem lf? and has at one side a chamber lil connected to the brake pipe 11 and. at the opposite side, a chamber ,1 9 contai ingr a coil spring.;- 20 acting on said pieton. There ie also a double beat valve 2l, adapted in one poeition to close coinniunication between chamber 19 and passage 22 and in the opposite normal position,` in` Which it ie held by the preeeure oil' spring 523, to cloee communication between spring chamber and the atmosphere. Said double beat valve has an extended stern provided With a push button 25 on its outer end, by which the double beat valve 2l is manually operated. t

The dietrilnitin valve device 2 comprises a casing); having the ueual application portion 26 and eqi'lalir/.ingr portion 27, and a valve device `for controlling theoperation oit the cut oli` valve` mechanism in the brake valve device. i t i i,

The dietriblusinfagl valve application portion coinprieee a casing;` having a piston Chamber 29=containing an application piston 30,-la-valve,chamber 31 containing an exhaust valve 32, and a valve chamber containing anappli'cation vvalve 34; said valvesfbeingv operated :by the movementV of the piston lstein 35.

kThe equalizing portionl 27 comprises a casing having a ,piston chamber 37 containing the equalizing piston 38 and` a valve chamber 39containing a: main slide valve "40, and an auxiliary-slide valve 41, adapt- Acfasingalso contains the usual pressure edv tof bel operated by said piston. Said y 'chamber 42 and application chamber 43.

Astemilof the equalizing piston 3S; The

stem* extensionr52i is fluted, so that when eolla'r'46' strikes' the inner side of wall 50, communication between valve chamber 44 f andpiston chamber 37 is maintained by way A throughpassage 62, containing 61?, land vinto spring chamber of'sai'dzflutes'and passage'87 in the wall 50.

Inoperation, with the brake valve device infrunning'position and the train brakes released, fluid at the reducedpressure supplied by "thefeed valve device 3, flows ,through pipe 53,. passage 54 in the brake valve Jdevice, cavity 55 in the rotary valve 5` andv thence through passa-ges 56 and 57 to chamber 8 at one side of the equalizing piston' and `from passage 57 through the choke 58 and" pipe 59 to the equalizing reservoir 9;?Flfuid at feed valve pressure also flows from the cavity 55m the rotar 1 valve 5, through port 60and thence into valve chamber 14,j and also from passage 60 a choke plug 19, which is connected' through passage 22, pipe 67 and passage L66 in the distributing valve device to the-.seat 'of the slide valve 45. In initially charging the brake system, the spring 49 acting on the collar 47 of the stem 48 holds .the 'slider valve 45 in the position Vshown lin the drawing, in 'which position passage ,66 is lapped, thus preventingV theescape of fluid supplied to spring chamber 19' by 0,way;otpassage 22, so that'opposing fluid pressures'in spring chamber v19 and valve chamber 141 are,l balanced, permitting the pressure ofspring20 to shift and hold the piston landivalve. 13 in the position shown ,y inthe drawing, in which position, fluid at feedvalve pressure from chamber 14 flows l sure in the brake to chamber 1S and thence through passage G3 to brake pipe 11, and to the equalizing piston chamber 1()` charging said brake pipe and chamber. The pressures thus being equalized on opposite sides of the equalizing piston`r the discharge valve 12 is held seated. Fluid under pressure from the brake pipe l1 flows 1through the branch pipe G4 to valve chamber 44 of the distributing valve device and thence through the passage 87 and past the fluted stem 52 to piston chamer 37 of the equalizing portion, `from which chamber said fluid is supplied through the .feed groove G5, around the piston 3S when in release position, to valve chamber 39, which is in communication with the pressure chamber 42, charging said chamber with fluid at bra-ke pipe pressure. Normally, the pressure of spring 23 holds rthe double beat valve 2l in the position shown in the drawing, in which position, said valve is seated so as to prevent escape to the atmosphere of the fluid under pressure that leaks from passage 22 through the clearance around the double beat valve stein in the casing and into the spring chamber 24.

lith the brake valve device in ruiming position and the equalizing portion 27 of thel distributing valve device in release pon sition, the application cylinder 29 is vented to the atmosphere through passages 69 and 70, cavity 71 in the equalizing slide valve 40, passage 72, the usual release pipe 73, passage 74 in the brake valve device, cavity 75 in the rotary valve 5 and the atmospheric passage 76. Then the application cylinder 29 is vented to the atmosphere, the application piston will be in the position shown in the drawing, in which the brake cylinder 77 is vented to the atmosphere through pipe 78, passage 79, valve chamber Bland atn'lospheric passage 80.

lV hen a sudden reduction in brake pipe pressure is initiated at some point in the train, said reduction is propagated serially throughout the train in the well known manner. Vhen the Wave of reduction in pressure reaches the locomotive, the presu pipe 11, the branch pipe G4, and the valve chamber 44, and piston chamber 37 of the distributing valve device, is suddenly reduced, causing the equalizingvpiston 38 to move to emergency position, in which it strikes the gasket 8l. Said movement causes the piston stem 51 to engage 'the yfluted stem extension 52 and shift said stem and the slide valve 45 to a position in which the cavity 82 connects passage 66 to the atmospheric passage S3. Passage 66 being connected through pipe 67 with chamber 19, the iiuid under pressure in said. chamber is vented to the atmosphere 'at a faster rate than it can be sie lll)

tion with. a brake pipe and a brake valve deificeliaviiig a position in Which fluid uiidei pressure is normally supplied to .the brake pipe to maintain the pressure .in the brake pipe at predetermined degree, of means operated upon a reduction in brake pipepressure in excess of a full servioereduction forcutting off' the supply of fluidL 'through said bralevalve device to the brake pipe.

3. In a fluid pressure brake,.the combina- Y 'tion iv-ith a brake pipe and a brake valve device having` a position in which. fluid under pressure. is 'normally supplied to the brake l )i Je of'a valve device o ierated. u )on a reduction in brake pipe pressure for applying' t-lie brakes and means operated by said valve device. for cuttiiifr ofi" the vsupply of fluid through said brake valve deviceto the brake pipe.

, v 2Q v y Lt-ion with a brake pipe anda brake valve de- -vice having a piston in which fluid under pressure is normally supplied to` the brake 4l. In a fluid pressurebrake,` the combinapipe, of a cut-oil valve device for controlling communication through which fluid is supplied from said brake valve device to the brake pipe, an equalizing slide valve-operated upon a reduction in brake pipe pressure fder pressure is normally suppliedv tothe brake pipe, of a cut-off valve device for controlling communication through which` fluid is supplied from said brake valve device to the brake'pipe, an equaliziue'. valve device operated upon a. reduction in brake pipe pressure for effecting an application of the brakes, and avalve operated upon movement of said equalizinnr valve device to apply the brakes foiteffecting Vthe operation of Isaid cutoff' valve device to close conmiunication through which said brake valvel device. supplies fluid vto the brake pipe.

6.111 a fluid pressure brake, the combination withl a. brake pipe and a brake valve device having'a position in ivhich fluid under pressure is normally supplied to the brake pipe, of a valve for controlling` communication through which .said brake valve device supplies fluid to the brake pipe, a piston operated by a variation in fluid under prcssure for operating` said falve, means for varying` the fluid under pressure on said piston, and a manually operable valve for cutting ofll communication through which fluid under pressure is varied on said piston.

7. In a fluid pressure brake, the combination Witha brake pipe and a brake valve device havingr a position in which fluid under pressure normally supplied to the brake pipe, of a valve for controlling,r communication through which said brake valve device supplies fluid tothe brake pipe, a pistonopei'at-ed upon a reduction in fluid pressure for operating said valve to close Said communication, means operated upon a, reduction in brake pipe pressure for venting fluid from said piston, and a manually controlled valve for cutting` off communication through which fluid under pressure is vented from said piston.

In testimony whereof I have hereunto set; my hand.

THOMAS H. THOMAS. 

